Clinical,pathological, therapeutic and prognostic analysis of primary membranous nephropathy in 218 children

Objective To analyze the clinical and pathological features, treatment and prognosis of primary membranous nephropathy (PMN) in children. Methods A retrospective study was conducted in patients with PMN diagnosed by renal biopsy in the Eastern Theater General Hospital from July 1, 2008 to September 30, 2017. The data of patients' general information, laboratory examination, renal pathology and therapeutic regimen were collected. The effects of different drugs in treatment and prognosis of PMN children were analyzed. Results Among 218 patients with PMN, the ratio of male to female was about 1.32∶1. The age group from 13 to 18 years old (adolescent) accounted for 87.6%, and there was no significant difference in age between the sexes (P=0.839). The main clinical manifestation was nephrotic syndrome (157 cases, 72.0%). The most common renal pathology stage was stageⅡ(101 cases, 46.3%). The positive rates of IgG1 and IgG4 in immunofluorescence staining were 100.0% and 98.5%, respectively, and IgG4 (45 cases, 33.8%) was the most common deposit. The positive rates of serum anti-PLA2R-Ab and kidney tissue PLA2R immunostaining were 53.97% and 82.54%, respectively. The total remission rate of PMN in children treated with tacrolimus combined with steroid was 83.6% and the recurrence rate was 33.3%. After follow-up time of 45.0(23.5-74.0) months, 11 cases (5.0%) developed end-stage renal disease (ESRD). The cumulative survival rates of ESRD at 5 and 10 years after renal biopsy were 95.4% and 63.7%, respectively. The cumulative renal survival rates of ESRD or a 30% decline in eGFR at 5 and 10 years after renal biopsy were 92.7% or 55.9%. Univariate Cox regression analysis demonstrated that hypertension and heavy proteinuria (24-hour urinary protein≥50 mg/kg) predicted a high risk of ESRD, and renal pathologic parameters were not associated with disease progression. Multivariate Cox regression analysis showed that hypertension (HR=9.517, 95%CI 1.181-76.715, P=0.034) and heavy proteinuria (HR=3.946, 95%CI 1.126-13.832, P=0.032) were independent risk factors for developing ESRD in PMN patients. However, the effectiveness of Cox regression analysis was analyzed by PASS software, and it was concluded that hypertension was not related with disease progression. Conclusions PMN should be considered in adolescent patients with nephrotic syndrome. Tacrolimus combined with steroid is more effective than steroid combined with other immunosuppressive agents in treating PMN. After follow-up time of 45.0(23.5-74.0) months, the prognosis of PMN children is acceptable. Heavy proteinuria is an independent risk factor for developing ESRD in children with PMN.